Olefin polymerization

ABSTRACT

Catalysts effective for the polymerization of olefins at high productivity formed upon mixing (1) a solution of a titanium tetrahydrocarbyloxide or a zirconium tetrahydrocarbyloxide and an organoaluminum halide with (2) a dihydrocarbylmagnesium compound alone or admixed with a minor amount of a trialkylaluminum and (3) combining the product obtained in (2) with a metal halide selected from a silicon tetrahalide and a titanium tetrahalide. The catalyst component thus produced can be combined with an organoaluminum compound as a cocatalyst component.

This is a divisional application of our parent Ser. No. 343,643, filedJan. 28, 1982, now U.S. Pat. No. 4,406,818.

BACKGROUND OF THE INVENTION

The invention relates to a composition of matter, a method of preparingsame, catalyst, a method of producing a catalyst and a process of usingthe catalyst. In another aspect, this invention relates to aparticularly effective ethylene polymerization catalyst and process.

In the production of polyolefins such as, for example, polyethylene,polypropylene, ethylene-butene copolymers, etc., an important aspect ofthe various processes and catalysts used to produce such polymers is theproductivity. By productivity is meant the amount or yield of solidpolymer that is obtained by employing a given quantity of catalyst. Ifthe productivity is high enough, then the amount of catalyst residuescontained in the polymer is low enough that the presence of the catalystresidues does not significantly affect the properties of the polymer andthe polymer either does not require additional processing or lessprocessing is needed to remove the catalyst residues. As those skilledin the art are aware, removal of catalyst residues from polymer is anexpensive process and it is very desirable to employ a catalyst whichprovides sufficient productivity so that catalyst residue removal is notnecessary or at least substantially reduced.

In addition, high productivities are desirable in order to minimizecatalyst costs. Therefore, it is desirable to develop new and improvedcatalysts and polymerization processes which provide improved polymerproductivities.

Accordingly, the object of the invention is to provide a catalyst.

Another object of the invention is to provide a polymerization processfor using a catalyst capable of providing improved polymerproductivities as compared to prior art catalysts.

Other objects, aspects, and the several advantages of this inventionwill be apparent to those skilled in the art upon a study of thisdisclosure and the appended claims.

SUMMARY OF THE INVENTION

In accordance with the invention, an active catalyst effective for thepolymerization of olefin monomers at high productivity is formed uponmixing (1) a solution of a titanium tetrahydrocarbyloxide or a zirconiumtetrahydrocarbyloxide and an organoaluminum halide with (2) adihydrocarbylmagnesium compound, alone or admixed with a minor amount ofa trialkylaluminum, and (3) combining the product obtained in (2) with ametal halide selected from among a silicon tetrahalide and a titaniumtetrahalide.

In accordance with one embodiment, a polymerization catalyst is preparedby

(1) forming a solution of an alkyl aluminum chloride and a titaniumalkoxide or a zirconium alkoxide,

(2) treating (1) with a dialkylmagnesium compound alone or admixed witha minor amount of a trialkylaluminum compound, and

(3) treating (2) with titanium tetrachloride or silicon tetrachloride.The catalyst (3) is used with aluminum alkyls to polymerize ethylene.

Further, in accordance with the invention, a method for producing theabove compositions is provided.

Further, in accordance with the invention, a catalyst is provided whichforms on mixing the above composition of matter and an organoaluminumcompound as a co-catalyst component.

Further, in accordance with the invention, aliphatic monoolefins arehomopolymerized or copolymerized with other 1-olefins, conjugateddiolefins, monovinylaromatic compounds and the like under polymerizationconditions employing the catalysts described above.

Further, in accordance with the invention, the above-described catalystis prepared by mixing together a titanium tetrahydrocarbyloxide compoundor a zirconium tetrahydrocarbyloxide compound and an organoaluminumhalide compound in a suitable solvent to produce a first catalystcomponent solution; a second catalyst component comprising adihydrocarbylmagnesium compound is added under suitable conditions tothe above-described first catalyst component solution in a manner so asto avoid a significant temperature rise in the solution to produce asolid composition in a form of a slurry with the solvent; thecomposition thus formed is then treated with a silicon tetrahalide ortitanium tetrahalide; and excess titanium or silicon tetrahalidecompound is removed from the resulting composition, for example, washedwith a hydrocarbon compound and dried to form an active catalystcomponent which can then be combined with a co-catalyst componentcomprising an organoaluminum compound.

DETAILED DESCRIPTION OF THE INVENTION

Suitable titanium tetrahydrocarbyloxide compounds employed in step (1)include those expressed by the general formula

    Ti(OR).sub.4

wherein each R is a hydrocarbyl radical individually selected from analkyl, cycloalkyl, aryl, alkaryl, and aralkyl hydrocarbon radicalcontaining from about 1 to about 20 carbon atoms per radical and each Rcan be the same or different. Titanium tetrahydrocarbyloxides in whichthe hydrocarbyl group contains from about 1 to about 10 carbon atoms perradical are most often employed because they are more readily available.Suitable titanium tetrahydrocarbyloxides include, for example, titaniumtetramethoxide, titanium tetraethoxide, titanium tetra-n-butoxide,titanium tetrahexyloxide, titanium tetradecyloxide, titaniumtetraeicosyloxide, titanium tetracyclohexyloxide, titaniumtetrabenzyloxide, titanium tetra-p-tolyloxide, titaniumtetraisopropoxide and titanium tetraphenoxide and mixtures thereof.Titanium tetraethoxide or titanium tetraisopropoxide is presentlypreferred because of especial efficacy in the process.

Catalysts derived from titanium tetraethoxide are very active and yieldpolymer at high productivity rates having a narrow molecular weightdistribution. Catalysts derived from titanium tetraiisopropoxide areless active but produce polymers exhibiting a broad molecular weightdistribution.

Suitable zirconium tetrahydrocarbyloxide compounds include thoserepresented by the formula

    Zr(OR).sub.4.nR.sup.4 OH

wherein R is as defined before, n is in the range of 0 to 2 and R⁴ OHrepresents an alcohol, preferably an alkanol having 1-10 carbon atoms.Generally, the radicals R and R⁴ are the same in the alcohol solvatedtetrahydrocarbyloxides. Examples of suitable zirconium compounds arezirconium tetramethoxide, zirconium tetraethoxide, zirconiumtetraisopropoxide isopropanol 1:1 molar complex, zirconiumtetradecyloxide, zirconium tetraeicosyloxide, zirconiumtetracyclohexyloxide, zirconium tetrabenzyloxide, zirconiumtetra-p-tolyloxide and zirconium tetraphenoxide and mixtures thereof.

The titanium alkoxide can be employed in a form complexed with analcohol, i.e., in the form Ti(OR)₄ nR⁴ OH, wherein R⁴ OH again is analcohol, preferably an alkanol with 1-10 carbon atoms.

Ti(OR)₄ and Zr(OR)₄ alkoxides can be made by reacting the correspondingtetrachloride, e.g., TiCl₄, with an alcohol, e.g., an alkanol having1-10 carbon atoms, in the presence of a HCl acceptor such as NH₃ asshown below; e.g.:

    TiCl.sub.4 +4EtOH+4NH.sub.3 →Ti(OEt).sub.4 +4NH.sub.4 Cl

    ZrCl4+4BuOH+4NH.sub.3 →Zr(OBu).sub.4 +4NH.sub.4 Cl

(Et=--C₂ H₅, Bu=--n--C₄ H₉)

If an excess of the alcohol is present, then the product alkoxide can besolvated with the alcohol. The alcohol is easier to remove from thesolvated Ti(OR)₄ than the solvated Zr(OR)₄. Thus, in complexescontaining alcohols, it is desirable or essential that the alcoholcomplexed is the same used in preparing the alkoxide as shown above.

The lower Ti alkoxides such as titanium tetraisopropoxide, Ti(O-i-C₃H₇)₄, can react with a higher alcohol to form the correspondingalkoxide, e.g., Ti(O-i C₃ H₇)₄ +4BuOH→Ti(OBu)₄ +4 i-C₃ H₇ OH. If thezirconium alkoxides react similarly, then the alcohol solvated complexesmust be tied to the alcohol used in their preparation as shown in thetwo equations above.

Mixtures of the hydrocarbyloxides of titanium and zirconium can also beemployed. However, no advantage in productivity appears to be gainedfrom doing this. It is presently preferred to use either the titanium orthe zirconium compound alone in preparing the catalyst and mostpreferably a titanium compound because of its cheaper cost and efficacyin the catalyst system.

A second catalyst component used in step (1) is generally anorganoaluminum halide compound which includes, for example,dihydrocarbylaluminum monohalides of the formula R₂ AlX,monohydrocarbylaluminum dihalides of the formula RAlX₂, andhydrocarbylaluminum sesquihalides of the formula R₃ Al₂ X₃ wherein eachR in the above formulas is as defined before and each X is a halogenatom and can be the same or different. Some suitable organoaluminumhalide compounds include, for example, methylaluminum dibromide,ethylaluminum dichloride, ethylaluminum diiodide, isobutylaluminumdichloride, dodecylaluminum dibromide, dimethylaluminum bromide,diethylaluminum chloride, diisopropylaluminum chloride,methyl-n-propylaluminum bromide, di-n-octylaluminum bromide,diphenylaluminum chloride, dicyclohexylaluminum bromide,dieicosylaluminum chloride, methylaluminum sesquibromide, ethylaluminumsesquichloride, ethylaluminum sesquiiodide, and the like. Polyhalidedcompounds are preferred.

The molar ratio of the titanium tetrahydrocarbyloxide compound orzirconium tetrahydrocarbyloxide compound to the organoaluminum halidecompound can be selected over a relatively broad range. Generally, themolar ratio is within the range of about 1:5 to about 5:1. The preferredmolar ratios are within the range of about 1:2 to about 2:1.

A titanium tetrahydrocarbyloxide compound or zirconiumtetrahydrocarbyloxide compound and organoaluminum halide compound arenormally mixed together in a suitable solvent or diluent which isessentially inert to these compounds and the product produced. By theterm "inert" is meant that the solvent does not chemically react withthe dissolved components such as to interfere with the formation of theproduct or the stability of the product once it is formed. Such solventsor diluents include hydrocarbons, for example, paraffinic hydrocarbonssuch as n-pentane, n-hexane, n-heptane, cyclohexane, and the like andmonocyclic and alkyl-substituted monocyclic aromatic hydrocarbons suchas benzene, toluene, the xylenes, and the like. Polymers produced withcatalysts prepared from an aromatic solvent and titaniumtetraiisopropoxide show broader molecular weight distributions, based onhigher HLMI/MI values, than polymers made with an aromaticsolvent-titanium tetraiisopropoxide-titanium tetraethoxide system. Thetetraiisopropoxide is more soluble in an aromatic solvent than aparaffin, hence such a solvent is preferred in producing that inventioncatalyst. The nature of the solvent employed is, therefore, related tothe type of metal hydrocarbyloxide employed. Generally, the amount ofsolvent or diluent employed can be selected over a broad range. Usuallythe amount of solvent or diluent is within the range of about 10 toabout 30 g per gram of titanium tetrahydrocarbyloxide.

The temperature employed during the formation of the solution of the twocomponents of step (1) can be selected over a broad range. Normally atemperature within the range of about 0° C. to about 100° C. is usedwhen solution is formed at atmospheric pressure. Obviously, temperaturesemployed can be higher if the pressure employed is above atmosphericpressure. The pressure employed during the solution-forming step is nota significant parameter. At atmospheric pressure good results areobtained from about 20°-30° C. and are presently preferred.

The solution of titanium compound of zirconium compound andorganoaluminum halide compound formed in step (1) is then contacted witha dihydrocarbylmagnesium compound alone or admixed with a minor amountof a trialkylaluminum. The organomagnesium compound can be expressed asMgR"₂ in which R" can be the same or different and each is a hydrocarbylgroup such as alkyl, cycloalkyl, aryl, aralkyl, and alkaryl containingfrom one to about 12 carbon atoms wherein presently preferred compoundsare dialkylmagnesium compounds in which alkyl group contains from 1 toabout 6 carbon atoms. Specific examples of suitable compounds includedimethylmagnesium, diethylmagnesium, and n-butyl-sec-butylmagnesium,di-n-pentylmagnesium, didodecylmagnesium, diphenylmagnesium,dibenzylmagnesium, dicyclohexylmagnesium and the like and mixturesthereof.

The molar ratio of tetravalent titanium compound employed in step (1) toorganomagnesium compound used in step (2) can range from about 5:1 toabout 1:2, preferably, from about 3:1 to about 1:1.

The trialkylaluminum compound can be expressed as AlR'₃ in which R' isan alkyl group containing from one to about 12 carbon atoms. Specificexamples of suitable compounds include trimethylaluminum,triethylaluminum, tri-n-butylaluminum, tridodecylaluminum, and the likeand mixtures thereof. By a minor amount in association with thedihydrocarbylmagnesium compound is meant from about 1 to about 25 molepercent trialkylaluminum.

The product formed after addition of organomagnesium compound in step(2) is treated with a metal halide selected from silicon tetrahalide ortitanium tetrahalide, preferably, titanium tetrachloride.

In step (3) the molar ratio of titanium tetrahalide to the combinedmoles of components of step (2) products can range from about 10:1 toabout 0.5:1, preferably, from about 2:1 to about 1:1.

After addition of titanium tetrahalide to the other catalyst componentsthe product formed can be recovered by filtration, decantation, and thelike. The product is preferably washed with a suitable material such asa hydrocarbon, for example, n-pentane, n-heptane, cyclohexane, benzene,xylenes, and the like to remove soluble material and excess titaniumcompound which may be present. Product can then be dried and storedunder any inert atmosphere. The products formed in this manner can bedesignated as catalyst A which can subsequently be combined with aco-catalyst B.

Co-catalyst component B is a metallic hydride or organometallic compoundwherein said metal is selected from Periodic Groups IA, IIA, IIIA of theMendeleev Periodic Table. The preferred compound to be used as componentB is an organoaluminum compound which can be represented by the formulaAlY_(b) R'"_(3-b) in which R'" is the same or different and is ahydrocarbon radical selected from such groups as alkyl, cycloalkyl,aryl, alkaryl, aralkyl, alkenyl and the like having from 1 to about 12carbon atoms per molecule, Y is a monovalent radical selected from amongthe halogens and hydrogen, and b is an integer of 0 to 3. Specificexamples of organoaluminum compounds include trimethylaluminum,triethylaluminum, triisobutylaluminum, tridodecylaluminum,tricyclohexylaluminum, triphenylaluminum, tribenzylaluminum,triisopropenylaluminum, diethylaluminum chloride, diisobutylaluminumhydride, ethylaluminum dibromide, and the like.

The amount of cocatalyst (component B) employed with the catalyst(component A) during polymerization can vary rather widely from about0.02 mmole per liter reactor contents to about 10 mmole per literreactor contents. However, particularly good results are obtained at amore preferred range of about 0.07 mmole per liter reactor contents toabout 2.5 mmole per liter reactor contents.

The polymerization process can be effected in a batchwise or in acontinuous fashion by employing any conventional mode of contact betweenthe catalyst system and the monomer or monomers. Thus the monomer can bepolymerized by contact with the catalyst system in solution, insuspension, or in gaseous phase at temperatures ranging from about20°-200° C. and pressures ranging from about atmospheric to about 1,000psia (6.9 MPa). The polymerization process can be conducted batchwisesuch as in a stirred reactor or continuously such as in a loop reactorunder turbulent flow conditions sufficient to maintain the catalyst insuspension. A variety of polymerizable compounds are suitable for use inthe process of the present invention. Olefins which can be polymerizedor copolymerized with the invention catalyst include aliphaticmono-1-olefins. While the invention would appear to be suitable for usewith any aliphatic monoolefin, olefins having 2 to 8 carbon atoms aremost often used and ethylene is particularly preferred.

The ethylene polymers produced are normally solid ethylene homopolymersor polymers prepared by copolymerizing ethylene alone or in combinationwith at least one aliphatic 1-olefin containing from 3 to about 10carbon atoms or a conjugated acyclic diolefin containing 4 or 5 carbonatoms. In such polymers, the ethylene content can range from about 80 to100 mole percent. The polymers can be converted into various usefulitems including films, fibers, pipe, containers, and the like byemploying conventional plastics fabrication equipment.

It is especially convenient when producing ethylene polymers to conductthe polymerization in the presence of a dry hydrocarbon diluent inert inthe process such as isobutane, n-heptane, methylcyclohexane, benzene,and the like at a reactor temperature ranging from about 60° C. to about110° C. and a reactor pressure ranging from about 250 to about 600 psia(1.7-4.1 MPa). In such a process, particle form polymerization, thepolymer is produced as discrete solid particles suspended in thereaction medium. The polymer can be recovered, can be treated todeactivate and/or remove catalyst residues, can be stabilized with anantioxidant system, and can be dried, all as known in the art to obtainthe final product. Also, molecular weight controls such as hydrogen canbe employed in the reactor as is known in the art to adjust themolecular weight of the product, if desired.

EXAMPLE I Catalyst Preparation

Generally, each catalyst was prepared by charging to a stirred 500 mLround bottom flask equipped for refluxing, when used, about 300 mL ofn-hexane, 0.035 mole of titanium tetraethoxide [Ti(OEt)₄ ] or titaniumtetraisopropoxide [Ti(O-i-Pr)₄ ] and 0.035 mole of ethylaluminumdichloride (EADC) as a 25 wt. % solution in n-heptane, all at roomtemperature (23° C.). The solution was stirred and then to it was added0.019 mole of n-butyl-sec-butylmagnesium (MgBu₂) as a 0.637 molarsolution in n-heptane over about a 20 minute period resulting in theformation of a slurry. Titanium tetrachloride, 0.192 mole, the halidetreating agent in this series, was added neat to the slurry and themixture stirred for one hour at room temperature or refluxed at 68° C.for one hour as indicated. The catalyst was recovered by allowing theslurry to settle, decanting a mother liquor and washing the slurry twicewith portions of n-hexane and twice with portions of n-pentane. Theproduct was dried over a warm water bath and stored in an inertatmosphere in a dry box until ready for use.

EXAMPLE II

Ethylene polymerization was conducted for 1 hour at 80° C. in a 3.8liter stirred, stainless steel reactor in the presence of isobutanediluent and 0.92 mole of triethylaluminum (TEA) as cocatalyst. Chargeorder was cocatalyst, catalyst and 2 liters diluent. Ethylene partialpressure was 0.69 MPa and total reactor pressure was 2.0 MPa. Ethylenewas supplied on demand from a pressurized reservoir as required duringeach run. Polymerization was terminated by venting ethylene and diluent.The polymer was recovered, dried and weighed to determine yields.Catalyst productivity is calculated by dividing polymer weight in gramsby catalyst weight in grams and is conveniently expressed as kg polymerper g catalyst per hour (kg/g/hr).

The titanium alkoxide used, halide treating temperature employed, moleratios used and results obtained are given in Table 1.

                                      TABLE 1                                     __________________________________________________________________________              Halide                                                                             Mole Ratios                                                              Treating        TiCl.sub.4                                                                              Cat.                                                                              Polymer                                                                            Calculated                       Run                                                                              Ti(OR).sub.4                                                                         Temp.                                                                              Ti(OR).sub.4                                                                       EADC  Combined  Wt. Wt.  Productivity                     No.                                                                              Used   °C.                                                                         EADC Mg Bu.sub.2                                                                         Organometal Cpds                                                                        mg  g    kg/g/hr                          __________________________________________________________________________    1.sup.(a)                                                                        Ti(OEt).sub.4                                                                        68   1:1  1.8:1 2:1       0.4 120  300                              2.sup.(a)                                                                        "      "    "    "     "         0.8   158.sup.(b)                                                                      198                              3  "      "    "    "     "         2.7 434  161                              4.sup.(a)                                                                        "      "    "    "     "         0.6 101  168                              5  "      23   "    "     "         1.4 283  202                              6  Ti(O--i-Pr).sub.4                                                                    "    "    "     "         6.4  44  6.8                              7.sup.(c)                                                                        Ti(OEt).sub.4                                                                        "    "    "     "         1.2 253  211                              8.sup.(d)                                                                        "      "    "    "     "         1.7 302  178                              __________________________________________________________________________     notes:                                                                        .sup.(a) Mixed organometal compounds at 0° C., warmed mixture to       23° C. and added TiCl.sub.4.                                           .sup.(b) Repeated polymerization with a second portion of run 1 catalyst.     .sup.(c) Mixed organometal compounds at 23° C., allowed solids to      settle washed them twice with nhexane, added TiCl.sub.4 to washed slurry.     .sup.(d) Mixed Ti(OR).sub.4 and EADC at 23° C. Heated to 68.degree     C., added Mg Bu.sub.2, then cooled to 23° C. and added TiCl.sub.4.

The data show with Ti(OEt)₄ -derived catalysts that variations in mixingconditions may alter catalyst activity somewhat but that generallyconsiderable latitude in said conditions can be tolerated. Thus,calculated catalyst productivities of about 200 kg/g/hr in the absenceof hydrogen at 80° C. is considered to be normal for the inventioncatalyst.

Poor results are noted with the Ti(O-i-Pr)₄ -derived catalyst based onone test only and may represent an anomalous result.

EXAMPLE III Control

A catalyst was prepared in the manner employed for the "standard"catalyst of run 5 except that TiCl₄ was omitted from the recipe.Ethylene polymerization was conducted at conditions identical to thoseof Example II with a 3.2 mg portion of the catalyst. Only a polymertrace resulted. Thus, the presence of a halide treating agent asexemplified by TiCl₄ is shown to be essential in the catalystpreparation.

EXAMPLE IV

Catalysts were prepared using the process employed for the standardcatalyst except that in one instance ethylaluminum sesquichloride (EASC)was used in place of EADC and in the other instance diethylaluminumchloride (DEAC) was used in place of EADC. Ethylene polymerization wasconducted with a portion of each catalyst as before. The results aregiven in Table 2.

                                      TABLE 2                                     __________________________________________________________________________                      Mole Ratios                                                    Organo-                                                                             Ti(OEt.sub.4)                                                                          Organoaluminum        Cat                                                                              Polymer                                                                            Calculated                    Run                                                                              aluminum                                                                            Organoaluminum                                                                         Halide    TiCl.sub.4 Wt. Wt.  Productivity                  No.                                                                              Halide                                                                              Halide   Mg Bu.sub.2                                                                             Combined Org. Cpds.                                                                      mg  g    kg/g/hr                       __________________________________________________________________________    1  EASC  1.8:1      1:1     2.5:1      1.2 209  174                           2  DEAC  1.7:1    1.1:1     2.4:1      5.5 286   52                           __________________________________________________________________________

The results show that ethylaluminum sesquichloride is about equivalentto ethylaluminum dichloride in preparing the invention catalyst based onthe calculated productivity but diethylaluminum chloride is not asefficient under these conditions as the polyhalide aluminum compounds.Thus, the DEAC-derived catalyst only exhibited about 0.3, the activityof the EASC-derived catalyst under the same polymerization conditions.

EXAMPLE V

A series of catalysts was prepared using the process employed for thestandard catalyst except that the level of EADC was varied. Ethylenepolymerization was conducted with a portion of each catalyst as before.The results are presented in Table 3.

                                      TABLE 3                                     __________________________________________________________________________            Mole Ratios             Cat.                                                                              Polymer                                                                            Calculated                           Run                                                                              mmoles                                                                             Ti(OEt).sub.4                                                                      EADC  TiCl.sub.4   Wt. Wt.  Productivity                         No.                                                                              EADC EADC Mg BU.sub.2                                                                         Combined Organic Cpds.                                                                     mg  g    kg/g/hr                              __________________________________________________________________________    1  0    0    0     3.4:1        1.6 140  87.5                                 2  0.017                                                                                2:1                                                                                1:1 2.6:1        4.1 318  77.6                                 3  0.027                                                                              1.3:1                                                                              1.4:1 2.2:1        2.8 210  75.0                                  4*                                                                              0.035                                                                                1:1                                                                              1.8:1   2:1        1.4 283  202                                  5  0.042                                                                              0.83:1                                                                             2.2:1 1.9:1        5.1 655  128                                  __________________________________________________________________________     *same as run 5, Table 1 (standard catalyst)                              

The results show that relatively active catalyst results even in theabsence of EADC (run 1). Runs 2, 3 suggest that catalysts prepared withEADC levels below that of the standard catalyst of run 4 are aboutequivalent or slightly poorer in activity than a catalyst prepared inthe absence of EADC. When the EADC level is increased to about 11/4times that employed in preparing the standard catalyst of run 4 then acatalyst is made having about 0.63 times the activity of the standardbut still about 1.5 times better than when no EADC is used.

EXAMPLE VI

A catalyst was prepared using the process employed for the standardcatalyst except that 18 mL of commercial preparation (Magala®),containing dibutylmagnesium (1.026 mg Mg/mL) and TEA (0.173 mmolesAl/mL) in hydrocarbon was employed in place of MgBu₂. Ethylenepolymerization was conducted with a 2.0 mg portion of catalyst as beforeyielding 339 g polyethylene. A calculated catalyst productivity of 169kg/g/hr resulted. Thus, an active catalyst is produced having about 0.84times the activity of the standard catalyst. This indicates that about15-20 mole percent of an organoaluminum compound can be substituted forthe organomagnesium compound to yield compositions which can be employedin preparing active catalysts.

EXAMPLE VII

A catalyst was prepared using the process employed for the standardcatalyst except that 1/2 the level of MgBu₂ was used (0.0095 mmoles vs0.019 mmoles for the standard catalyst) and the halide treatmentoccurred at 68° C. Ethylene polymerization was conducted with a 2.2 mgportion of the catalyst as before yielding 138 g polyethylene giving acalculated catalyst productivity of 62.7 kg/g/hr. The calculated moleratios are: Ti(OEt)₄ :EADC=1:1, EADC/MgBu₂ =3.7:1 and TiCl₄ :combinedorganometal compounds=2.4:1. Thus, decreasing the level of MgBu₂ to 1/2that normally used decreases catalyst activity to about 0.3 that of thestandard catalyst.

EXAMPLE VIII

Several catalyst were prepared using the general process employed forthe standard catalyst except that the halide agent employed was SiCl₄,0.175 moles in one instance and 0.349 moles in the other, instead of the0.182 moles of TiCl₄ used in the standard catalyst. Ethylenepolymerization was conducted as before. The results are given in Table4.

                                      TABLE 4                                     __________________________________________________________________________                                      Calculated                                  Mole Ratios              Cat.                                                                              Polymer                                                                            Catalyst                                    Run                                                                              Ti(OEt).sub.4                                                                      EADC  SiCl.sub.4 Wt. Wt.  Productivity                                No.                                                                              EADC Mg BU.sub.2                                                                         Combined Org. Cpds.                                                                      mg. g    kg/g/hr                                     __________________________________________________________________________    1  1:1  1.8:1 2.0:1      1.2  44  36.7                                        2  1:1  1.8:1 3.9:1      2.2 150  68.2                                        __________________________________________________________________________

The results indicate that catalysts prepared with SiCl₄ instead of TiCl₄do not yield catalysts as active in ethylene polymerization. Compared tothe results employed with the standard catalyst (run 5, Table 1), run 1catalyst shows about 0.2 the activity of the standard catalyst and run 2catalyst shows about 0.3 the activity of the standard catalyst.

In the following series, ethylene polymerization was conducted in the3.8 liter reactor employing a reactor temperature of 100° C., anethylene partial pressure of 1.38 MPa, a hydrogen partial pressure of0.345 MPa (unless indicated otherwise), 0.92 mmole of TEA as cocatalystas before (unless indicated otherwise) and 2 liters of isobutanediluent.

EXAMPLE IX

A standard catalyst was prepared as described in run 5, Table 1. A 7.0mg portion of it was employed in ethylene polymerization with 0.345 MPahydrogen partial pressure and 3.83 MPa total reactor pressure. A second4.8 mg portion of the catalyst was employed in ethylene polymerizationwith 0.827 MPa hydrogen partial pressure and 4.38 MPa total reactorpressure.

A second catalyst was prepared in a variation of the standard catalystas described in run 7, Table 1. A 7.6 mg portion of it was employed inethylene polymerization with 0.414 MPa hydrogen partial pressure and3.69 MPa total reactor pressure.

The results with melt index (MI), high load melt index (HLMI) andHLMI/MI ratios are given in Table 5.

                  TABLE 5                                                         ______________________________________                                        Calculated      Polymer Properties                                                 Catalyst                             Bulk                                Run  Productivity                                                                             TEA                HLMI   Density                             No.   kg/g/hr   mmole   MI   HLMI  MI     g/cc                                ______________________________________                                        1    60.3       0.46    0.51 16.5  32     not made                            2    51.5       "       11.  273   25     not made                            3    41.1       0.92    3.0  80.3  27     0.32                                ______________________________________                                         MI  ASTM D 123873, condition E; g/10 minutes, 2160 g total load               HLMI  ASTM D 123873, condition F; g/10 minutes, 21,600 g total load           HLMI/MI  A ratio which indicates the molecular weight distribution. The       higher the ratio, the broader the molecular weight distribution and           greater the shear response of the polymer.                               

The results show the invention catalyst to be responsive to hydrogen asthe melt index values of the polymers show. The polymer bulk densityshown in run 3 indicates that the polymer "fluff" (as made polymer) canbe processed in conventional equipment and that commercially usefulpolymer can be made. The HLMI/MI ratios shown are considered to benormal for titanium-based catalysts and are relatively narrow molecularweight distribution polymers.

The effect of the hydrogen is to reduce catalyst productivity anddecrease polymer molecular weight as the hydrogen concentrationincreases. These effects are normal for the titanium-based catalysts.

EXAMPLE X

Several catalysts were prepared in this series. One was made by mixingabout 300 mL of n-hexane, 0.035 mole of Ti(OEt)₄ and 18 mL of Magala® atabout 23° C. as described in Example VI. To the stirred mixture wasadded 0.211 mole of VOCl₃ and the slurry stirred for 1 more hour atabout 23° C. The catalyst was recovered as before. A 71.5 mg portion wasused in ethylene polymerization (run 1, Table 6).

A portion of the catalyst used in run 1, Table 4 was employed as thesecond catalyst. A 15.7 mg portion of it was employed in ethylenepolymerization (run 2, Table 6).

In each run, the hydrogen partial pressure was 0.414 MPa and 0.92 mmoleTEA was used as cocatalyst. The results are shown in Table 6.

                  TABLE 6                                                         ______________________________________                                        Calculated                                                                    Catalyst       Polymer Property                                               Run     Productivity               HLMI                                       No.     kg/g/hr    MI        HLMI  MI                                         ______________________________________                                        1       1.10       1.05      45    43                                         2       28.6       1.9       48    25                                         ______________________________________                                    

The results demonstrate in run 1 that VOCL₃ is not an effectivesubstitute for TiCl₄ in preparing active catalysts in this invention asthe low productivity value obtained clearly shows. On the other hand, inthis instance, SiCl₄ is seen to give a moderately active catalyst.

EXAMPLE XI

Three catalysts were prepared in this series. In (1) about 300 mL ofmixed xylenes (as commercially sold), 0.035 mole of Ti(O-i-Pr)₄ and0.035 mole of EADC were mixed together at about 23° C. (roomtemperature). To the stirred mixture at room temperature was added 0.019mole of MgBu₂ as before. Finally, 0.182 mole of TiCl₄ was added, themixture was stirred and the catalyst was recovered as before. In (2), amixture containing about 200 mL of mixed xylenes, 5 g (0.011 mole) of a1:1 molar complex of Zr(O-i-Pr)₄.i-C₃ H₇ OH and 0.017 mole of EADC asbefore. Finally, 0.182 mole of TiCl₄ was added, the mixture was stirredand the catalyst was recovered as before. In (3) the same procedure wasfollowed as in (2) except that 2.5 g (0.0064 mole) of theZr(O-i-Pr)₄.i-C₃ H₇ OH complex and 0.0064 mole of Ti(O-i-Pr)₄ wereemployed in place of the complex.

Ethylene polymerization was conducted as before with a hydrogen partialpressure of 0.345 MPa and 0.46 mmole TEA as cocatalyst. A 32.8 mgportion of catalyst was used in run 1, 14.3 mg of catalyst 2 used in run2 and 12.4 mg of catalyst 3 used in run 3.

                  TABLE 7                                                         ______________________________________                                        Calculated Catalyst                                                                            Polymer Productivitv                                         Run    Productivity                 HLMI                                      No.    kg/g/hr       MI       HLMI  MI                                        ______________________________________                                        1      25.3          0.21     9.8   47                                        2      8.88          0.13     8.4   65                                        3      11.9          0.31     15    48                                        ______________________________________                                    

The results in run 1 suggest that moderately active catalysts can bederived from Ti(O-i-Pr)₄ when the hydrocarbon reaction medium incatalyst preparation is xylene rather than n-hexane as employed for theotherwise identical catalyst of run 6, Table 1. In that run, aproductivity of only about 7 kg/g/hr was obtained compared to about 200kg/g/hr for the standard catalyst. In this series the Ti(O-i-Pr)₄-derived catalyst gave 25.3 kg/g/hr which can be compared with theresults under identical conditions for the standard catalyst in run 1,Table 5 of 60.3 kg/g/hr.

The results in runs 2, 3 indicate that only fairly active catalysts canbe derived from the zirconium alkoxide-isopropanol complex or thecomplex admixed with an equimolar amount of Ti(O-i-Pr)₄. However, in run2 with the catalyst derived from the zirconium alkoxide-alkanol complex,the polymer produced therewith had a HLMI/MI value of 65, indicative ofa polymer with a broad molecular weight distribution.

EXAMPLE XII

Two catalysts previously described, one in Example VI and the other ofrun 1, Table 7, renumbered 1 and 4, respectively in this series, and twonew catalysts are employed in this series. Catalysts 2, 3 were preparedin the general manner described for catalyst 4 in which a mixed xylenesreaction medium is used.

Catalyst 2 was prepared by mixing abut 250 mL of mixed xylenes, 0.023mole of Ti(OEt)₄, 0.012 mole of Ti(O-i-Pr)₄, 0.035 mole of EADC, 0.019mole of MgBu₂ and 0.182 mole of TiCl₄. Catalyst 3 was prepared by mixingabout 250 mL of mixed xylenes, 0.012 mole of Ti(OEt)₄, 0.023 mole ofTi(O-i-Pr)₄, 0.019 mole of MgBu₂ and 0.182 mole of TiCl₄.

Ethylene polymerization was conducted as before with a portion of eachcatalyst for 1 hour at 100° C. and 1.38 MPa ethylene partial pressure in2 liters of isobutane and the indicated hydrogen partial pressure. Inone series, 0.5 mmole TEA was used as cocatalyst along with 0.34 MPahydrogen partial pressure. In a second series, 0.4 mmole oftriisobutylaluminum (TIBA) was used as cocatalyst along with 0.34 MPahydrogen partial pressure. In a third series, DEAC of the indicatedconcentration, was used as cocatalyst along with 0.69 MPa hydrogenpartial pressure. The results are given in Table 8.

                                      TABLE 8                                     __________________________________________________________________________    Titanium Alkoxide Source                                                                    2/3Ti(OEt).sub.4                                                                      1/3Ti(OEt).sub.4                                               Ti(OEt).sub.4                                                                        1/3Ti(0--i-Pr).sub.4                                                                  2/3Ti(0--i-Pr.sub.4)                                                                  Ti(0--i-Pr).sub.4                               __________________________________________________________________________    Run No.                                                                              1A     1B      1C      1D                                              Cocatalyst                                                                           TEA (0.46)                                                                           TEA (0.46)                                                                            TEA (0.46)                                                                            TEA (0.46)                                      (mmole)                                                                       Catalyst (mg)                                                                        5.5    7.3     11.1    7.0                                             Productivity                                                                         64.7   41.8    21.4    25.3                                            (kg/g/hr)                                                                     MI     1.2    0.53    2.2     0.21                                            HLMI/MI                                                                              30     29      34      47                                              Run No.                                                                              2A     2B      2C      2D                                              Cocatalyst                                                                           TIBA (0.4)                                                                           TIBA (0.4)                                                                            TIBA (0.4)                                                                            TIBA (0.4)                                      (mmole)                                                                       Catalyst (mg)                                                                        4.3    7.3     10.5    6.5                                             Productivity                                                                         67.9   47.1    71.6    34.6                                            (kg/g/hr)                                                                     MI     1.2    1.2     1.1     0.39                                            HLMI/MI                                                                              28     33      34      53                                              Run No.                                                                              3A     3B      3C      3D                                              Cocatalyst                                                                           DEAC (1.3)                                                                           DEAC (2.1)                                                                            DEAC (2.1)                                                                            DEAC (4.2)                                      (mmole)                                                                       Catalyst (mg)                                                                        3.5    6.5     13.9    16.9                                            Productivity                                                                         61.1   34.6    19.1    3.49                                            (kg/g/hr)                                                                     MI     0.21   0.47    0.59    0.98                                            HLMI/MI                                                                              29     38      54      95                                              __________________________________________________________________________

The results show that the nature of the titanium alkoxide used inpreparing the catalyst can profoundly affect the activity of thecatalyst as well as the molecular weight distribution of the polymermade with the catalyst. Thus, titanium tetraiisopropoxide is favored inproducing broad molecular weight distribution polymers and titaniumtetraethoxide is preferred when high productivity and narrow molecularweight distribution polymers are desired.

We claim:
 1. A process for the polymerization of olefins which comprisescontacting at least one aliphatic 1-olefin under polymerizationconditions with a catalyst consisting essentially of the catalyticreaction product which is formed by(1) preparing a hydrocarbon solutionof a titanium tetrahydrocarbyloxide compound and an organoaluminumhalide compound; (2) contacting the solution formed in step (1) with anorganomagnesium compound alone or admixed with a minor amount of atrialkylaluminum to form a complex; (3) reacting the product obtained instep (2) with a metal halide which is a silicon tetrahalide or atitanium tetrahalide to form a precipitate; and (4) combining theprecipitate product obtained in step (3) with an organoaluminumcocatalyst compound to form an active polymerization catalyst.
 2. Aprocess according to claim 1 wherein the olefin is ethylene.
 3. Aprocess according to claim 2 wherein said polymerization is carried outin the presence of hydrogen to adjust the molecular weight of theproduct.
 4. A process for the polymerization of olefins according toclaim 1 wherein the titanium tetrahydrocarbyloxide is a titaniumalkoxide in which the alkyl group of the alkoxide contains from 1 to 20carbon atoms, the organoaluminum halide compound can be expressed asmonohalides of the formula R₂ AlX, dihalides of the formula RAlX₂, andsesquihalides of the formula R₂ Al₂ X₃ in which R is a hydrocarbyl grouphaving from 1 to 20 carbon atoms, and each X is a halogen atom and canbe the same or different, and the organomagnesium compound can beexpressed as MgR"₂ in which R" is a hydrcarbyl group containing from 1to 12 carbon atoms and trialkylaluminum, if present can be expressed asAIR' in which R' is an alkyl group having 1 to 12 carbon atoms and themetal halide is titanium tetrahalide.
 5. A process according to theclaim 4 wherein the olefin is ethylene.
 6. A process according to claim5 wherein said polymerization is carried out in the presence of hydrogento adjust the molecular weight of the product.
 7. A process according toclaim 5 for the production of broader molecular weight distributionpolymer, based on higher HLMI/MI values, wherein said titanium compoundis titanium isopropoxide.
 8. A process according to claim 5 for theincreased production of narrow molecular weight distribution polymerwherein said titanium compound is titanium tetraethoxide.
 9. A processaccording to claim 1 wherein (1) is a solution of titanium tetraethoxideand ethylaluminum dichloride; (2) is a solution of (1) which iscontacted with n-butyl-sec-butylmagnesium; (3) the product of step (2)is reacted with titanium tetrachloride, and the product of (3) iscombined in (4) with diethylaluminum chloride, triisobutylaluminum ortriethylaluminum.
 10. A process according to claim 1 wherein the molarratio of titanium tetrahydrocarbyloxide compound to organoaluminumhalide compound in step (1) ranges from 5:1 to 1:5; the molar ratio oftetravalent titanium compound in step (1) to organomagnesium compound instep (2) ranges from 5:1 to 1:2; and the molar ratio of titaniumtetrahalide added in step (3) to the combined moles of components ofstep (2) ranges from about 10:1 to about 0.5:1.
 11. A process accordingto claim 1 wherein the catalyst is formed by(1) preparing a hydrocarbonsolution of titanium tetraethoxide or titanium tetraisopropoxide, andethylaluminum sesquichloride or diethylaluminum chloride, (2) contactingthe solution of (1) with dibutylmagnesium or dibutylmagnesium and aminor amount of triethylaluminum, (3) reacting the product obtained instep (2) with titanium tetrachloride, and (4) combining the product of(3) with triethylaluminum.
 12. A process according to claim 11 wherein(2) is formed by contacting (1) with a mixture of dibutylmagnesium andtriethylaluminum containing about 1-25 mole percent triethylaluminum.13. A process for the polymerization of ethylene under polymerizationconditions in the presence of a catalyst consisting essentially of thereaction product which is formed by(1) admixing together a titaniumtetrahydrocarbyloxide compound, an organoaluminum halide compound and ahydrocarbon to produce a first catalyst component solution, (2)contacting the first catalyst component solution in (1) with anorganomagnesium compound alone or in admixture with a minor amount of atrialkylaluminum compound to form a complex, (3) reacting the complex ofstep (2) with a titanium tetrahalide to form a precipitate, and (4)combining the precipitated product formed in step (3) with a co-catalystcomponent B which is an organoaluminum compound.
 14. A process accordingto claim 13 wherein the catalyst is prepared by(1) forming a paraffinicor aromatic hydrocarbon solution of an alkylaluminum dichloride and atitanium alkoxide, (2) combining (1) with a dialkylmagnesium compoundalone or in admixture with a minor amount of trialkylaluminum compound,(3) reacting (2) with titanium tetrachloride, (4) removing unreactedtitanium tetrachloride from the product formed in (3), and (5) combiningthe product of (4) with a trialkylaluminum.
 15. A process according toclaim 14 comprising(1) preparing a n-hexane or mixed xylenes solution oftitanium tetraethoxide or titanium tetraisopropoxide and ethylaluminumdichloride, ethylaluminum sesquichloride or diethylaluminum chloride,(2) containing the solution of (1) with dibutylmagnesium ordibutylmagnesium and a minor amount of triethylaluminum, (3) reacting(2) with titanium tetrachloride, (4) removing unreacted titaniumtetrachloride from the product formed in (3), and (5) combining theproduct of (3) with triethylaluminum.
 16. A process according to claim13 wherein the final product in (3) is washed with an inert solvent toremove unreacted metal halide compound prior to combining with componentB and the reactants are contacted at a temperature in the range of about0°-100° C.